An android complex enough to warrant individuality and military command cannot make contractions, apparently one of the great boons of being human. Ain't it.
To be sure, that's something of a myth. Data never claims he cannot make contractions. He only asserts that he speaks very carefully, whether it be out of choice or due to his upbringing.
When "he" does not, in the simulation of TNG "Future Imperfect", Riker gets confirmation for his already established belief that this "Data" is but a fake, and thus he flaunts that piece of evidence at the fake - but that's as close as anybody ever comes to claiming that Data "cannot" use contractions. Indeed, every episode, from the first one onwards, stands proof that he can.
Don't know if it qualifies, but the beings in the wormhole in DS9 that live outside of time, have no concept of time, yet are waiting for the Sisko and the fulfillment of a prophecy.
That makes perfect sense, really. When Sisko visits them in DS9 "Emissary", they learn about the concept of linear time - but since they are still nonlinear by nature, this learning process affects their past, not just their future... They only start waiting for Sisko as the result of Sisko's arrival!
Entire cultures / species / planetfuls of people who have identical hairstyles and wear identical clothing? How is that anything other than ridiculous?
To be fair, we usually only see some officials or soldiers from the given planet, and at most visit one city on the surface. Such small pools of people would actually be likely to be homogeneous: the official representatives of a world would have an official dress code, and the inhabitants of a city would have a "city identity".
Did we ever visit multiple locations on a planet and witness similar homogeneity? Bajor was culturally diverse enough, between episodes like "Progress" or "The Storyteller" or "The Circle". The classic Vulcan hairstyle could be a governmental peculiarity, much as the wigs of British courts, as we do see other styles every now and then, usually on Starfleeters or other outcasts. And Romulans could be so uniform simply because they are so totalitarian.
Timo Saloniemi